This invention relates to a golf ball having dimple groupings optimized for excellent aerodynamic performance.
In general, golf balls have a plurality of dimples on their surface for improving the aerodynamic performance thereof. In order that the golf ball as launched travel a longer carry, the rebound upon impact of the ball itself and the reduced air resistance of the ball in flight due to the arrangement of dimples on the ball surface are key factors as is well known in the art. In connection with the reduction of air resistance, a number of methods have been proposed for arranging dimples throughout the ball surface as uniformly and densely as possible. One typical dimple arrangement uses as base units hexagonal groups each having seven, in total, circular dimples assembled together, establishing a high density dimple arrangement.
However, the above-mentioned dimple arrangement is still insufficient in uniformity of dimple distribution and difficult to distribute dimples uniformly and closely throughout the ball""s spherical surface. Besides, regular polyhedral dimple arrangement patterns such as regular octahedral and icosahedral patterns are also known, but yet somewhat deficient in close packing of dimples.
An object of the present invention is to provide a golf ball having a plurality of dimples arranged as uniformly and densely as possible for imparting improved flight uniformity and flight performance.
The invention relates to a golf ball having a pair of opposed poles and a plurality of dimples on its surface. It has been found that when pentagonal groups each consisting of five dimples arranged about one central dimple are dispersively distributed at twelve locations over the ball surface excluding the polar areas, and hexagonal groups each consisting of six dimples arranged about one central dimple are distributed over the remaining area of the ball surface, the dimples can be arranged uniformly and at a high density so that the ball is endowed with uniform behavior in flight and significantly improved in distance.
According to the present invention, there is provided a golf ball having a pair of poles and a plurality of dimples on its surface, wherein twelve pentagonal groups each consisting of five dimples arranged about one central dimple are dispersively distributed over the ball surface excluding the polar areas, and hexagonal groups each consisting of six dimples arranged about one central dimple are distributed over the remaining area of the ball surface. The term xe2x80x9cdispersivelyxe2x80x9d means that the pentagonal groups are spaced apart from each other.
In a preferred embodiment, the central dimple of the hexagonal group is located at or near either pole of the ball.
In another preferred embodiment, a portion of the pentagonal group constitutes a portion of the hexagonal group.
The dimples are circular in most cases. In one embodiment, except for those dimples located at the center of the pentagonal groups, the dimple edges delimiting each dimple define together a hexagonal shape.
The golf ball has between the pair of poles an equator by which the ball is divided into a pair of hemispheres. In a preferred embodiment, six pentagonal groups are dispersively distributed on one hemisphere and six pentagonal groups are dispersively distributed on the other hemisphere.
Preferably, the pentagonal groups are distributed in symmetry with respect to an axis of rotation that connects the pair of poles.
Also preferably, the total of dimple areas accounts for at least 77% of the entire surface area of the golf ball.
In the pentagonal group, the central dimple is smaller than the surrounding dimples. In an alternative embodiment, the central dimple in the pentagonal group is not smaller than the surrounding dimples.